This is a sidebar to " Slaying the Partisan Gerrymander ," which appears in the Fall 2017 issue of The American Prospect magazine. Subscribe here . W hen it comes to creating a test for detecting gerrymanders, getting stuck on the details of maps hinders an efficient evaluation. Courts need simple and straightforward tools for detecting gerrymanders. Partisan gerrymandering is perpetrated using two complementary methods: cracking and packing. “Packing” occurs when as many supporters of one party as possible are crammed into a small number of districts, creating a few overwhelming wins for the victim party. The remaining members of the victim party are then “cracked,” or spread evenly across a large number of districts that the gerrymandering party can dominate. Fortunately, cracking and packing create a distinctive statistical pattern that can be detected with the help of a little math. Two tests, Student’s t-test and the mean-median difference, probe whether a districting scheme is...